I noticed that the visual effect of the Swarm strike (sort of tornado around the character) stays on even after the timer’s finished. It MIGHT occurs more frequently when using Barrage of the Swarm and Swarm’s fury (shapeshifting between different forms).
I’m having the same issue, verifying game files didn’t work, haven’t been able to find repro steps yet. I’ve had it where I go from one area to another and the visual effect turns on by itself, when it was off before.